Department of Animal and Food Sciences

Limin Kung, Jr., Ph.D.

Why Cows Are Cool

Ruminants (e.g. cows, sheep, and deer) are metabolic marvels because of interactions with microbes in their guts. Ruminants have three forestomachs where bacteria and protozoa ferment feed. These microbes produce volatile fatty acids and microbial protein that are utilized as sources of energy and protein, respectively by the animal. In a lactating cow, the first two forestomachs, the rumen and reticulum, have a capacity of about 150 to 200 liters. Each liter of rumen fluid contains about 1011 bacteria, 106 protozoa, and 103 fungi per ml. Interestingly, ruminants are born with metabolic processes based on the primary absorption of glucose and a gastrointestinal system that is very similar to a monogastric animal (e.g., a pig). However, as the animal matures, primary metabolism shifts to an organic acid economy, based mostly on the absorption of acetic and propionic acids from the rumen. My lab conducts research in the areas of ruminant nutrition and microbiology with the goal of improving the productive efficiency of ruminants.